This edited volume represents state of the field research linking cognition and second language acquisition, reflecting the experience of the learner when engaged in noticing, input/output processing, retrieval, and even attrition of target forms. Contributions are both theoretical and practical, describing a variety of L1, L2 and L3 combinations from around the world as observed in spoken, written, and computer-mediated contexts. The book relates conditions of language, task, medium or environment to how learners make decisions about language, with discussions about the application or efficacy of these conditions on linguistic success and development, and pedagogical implications.